The prior art is replete with various onboard vehicle systems, instrument devices, gauges, and instrument displays. The number and type of vehicle instruments and displays can vary from one vehicle model to another, from one vehicle platform to another, and the like. In this regard, fully electric and hybrid electric vehicles may utilize instrumentation and gauges that are specific to those types of vehicles. For example, fully electric and hybrid electric vehicles may include displays that indicate the operating status of the electric power system, the battery charge level, and the like.
The popularity of hybrid electric, plug-in hybrid, and fully electric vehicles continues to increase over time. Accordingly, the prior art is replete with different systems, control technologies, and processes related to the operation of such vehicles. A hybrid electric vehicle (HEV) includes a rechargeable energy storage system (ESS) which is usually configured as a rechargeable battery or battery pack having a relatively high energy density. An HEV can also include a gasoline, diesel, or alternative fuel internal combustion engine. Other vehicle designs may employ a fuel cell and/or another power source in place of or in conjunction with an internal combustion engine in order to further reduce vehicle emissions and improve the operating range of the vehicle. A fully electric vehicle (EV) only includes an electric drive train, e.g., an electric motor and an ESS.
In certain HEV and EV designs, the drive wheels of the vehicle remain continuously connected to the driveline to enable regenerative braking capability, thus providing a relatively efficient means of capturing useful and otherwise wasted braking energy during coast-down and/or during active braking. As is known in the art, an electric motor/generator (MOGEN) can be selectively operated in such a manner as to allow the device to act as a generator during coast-down or an active regenerative braking event. When acting as a generator, the electric MOGEN recharges the ESS while applying a negative torque to the drive wheels and/or the drive shaft, thus electronically slowing the vehicle. The electric MOGEN likewise can be selectively operated as an electric motor, thus drawing stored electrical energy from the ESS as needed to propel the vehicle. Regeneration during coast-down or active braking contributes to the deceleration of the vehicle. In this regard, negative braking regenerative torque can be applied as a function of brake pedal travel to mimic the characteristics of a standard vacuum-based hydraulic brake system. In practice, braking regenerative torque can be applied as an additive torque to the friction brake torque (which is generated in response to driver actuation of the brake pedal).
Conventional energy/power gauges in HEVs and EVs usually indicate when the ESS is delivering traction power and/or when the ESS is being charged via regenerative braking or coasting. Such power gauges saturate at the maximum charging power level. Consequently, these conventional energy/power gauges do not indicate a dynamic threshold between regenerative braking power and friction braking power.
Accordingly, it is desirable to have an improved methodology and related instrument display system that accurately indicates regenerative and friction braking power in real-time onboard a host vehicle. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.